Case Study:

During a busy flu season, a city hospital increased the use of alcohol-based sanitisers in patient rooms, waiting areas, and operating theatres. The sanitiser bottles mentioned “70% ethanol” on their labels. Nurses observed that after applying the sanitiser on hands or metal surfaces, the liquid disappeared within a few seconds, yet laboratory reports showed a major reduction in harmful bacteria and viruses.

The hospital management became curious about how a simple carbon compound could clean surfaces so effectively while evaporating so quickly. A science intern explained that ethanol is a carbon compound containing a hydroxyl group (–OH).

Because carbon forms the backbone of millions of vital compounds like ethanol, it's fascinating to explore why carbon is called the king of elements in chemistry and how it shapes our world.

Due to its chemical properties, ethanol mixes easily with water and spreads quickly on surfaces. Its fast evaporation helps surfaces dry rapidly, while its chemical action damages the protective covering of many microorganisms, making them inactive.

This entire process relies on how atoms share electrons to stay stable. If you want a quick, visual refresher on how these structures form, check out these fun ways to understand covalent bonding with diagrams.

In another experiment, the hospital staff compared two sanitisers - one containing only water and another containing 70% ethanol. After 30 seconds of use, the ethanol-based sanitiser showed nearly 95% germ reduction, while the water-based liquid showed very little effect.

The staff also learned that ethanol can react with ethanoic acid in the presence of concentrated sulphuric acid to form sweet-smelling esters. This reaction is widely studied in chemistry because it shows the chemical behaviour of ethanol and ethanoic acid.

The investigation helped students understand why ethanol is considered both a useful chemical compound and a lifesaving substance in hospitals.

CASE-BASED QUESTIONS

 MCQ 

Q1. Why does ethanol-based sanitiser dry quickly on the skin?
(a) Ethanol freezes rapidly
(b) Ethanol evaporates easily
(c) Ethanol absorbs water completely
(d) Ethanol reacts with oxygen immediately

Q2. Which functional group is present in ethanol?
(a) –COOH
(b) –CHO
(c) –OH
(d) –CO–

 Assertion - Reason 

Q3. Assertion (A): Ethanol is commonly used in hospital sanitizers.
Reason (R): Ethanol can evaporate quickly and help destroy microorganisms.
(a) Both A and R are true, and R is the correct explanation of A.
(b) Both A and R are true, but R is not the correct explanation of A.
(c) A is true, but R is false.
(d) A is false, but R is true.

 Application-Based  

Q4. A student used pure water instead of sanitiser to clean a laboratory table. Explain why the cleaning effect was less effective compared to the ethanol sanitiser.

Context Tip:  While ethanol is excellent for sanitising surfaces, daily cleaning often requires a different chemical approach. To understand how everyday cleaning agents lift dirt, read about soaps vs detergents and what Class 10 Chemistry teaches us regarding their molecular action.

Q5. In the hospital experiment, why was 70% ethanol considered more useful than plain water for reducing germs on surfaces?

 Data/Logic-Based 

Q6. Observe the data from the hospital test:

Based on the data, what conclusion can be drawn about ethanol?
(a) Ethanol has no role in sanitation
(b) Water destroys more germs than ethanol
(c) Ethanol is effective in reducing microorganisms quickly
(d) Ethanol increases bacterial growth

 Application + Reasoning  

Q7. Ethanol reacts with ethanoic acid in the presence of concentrated sulphuric acid. Name the type of reaction and mention one product formed.

ANSWER KEY WITH EXPLANATION

A1. (b) Ethanol evaporates easily
Explanation: Ethanol is a volatile liquid. Due to its low boiling point, it evaporates quickly from surfaces, causing fast drying.

A2. (c) –OH
Explanation: Ethanol belongs to the alcohol family and contains the hydroxyl (–OH) functional group according to the NCERT classification.

A3. (a) Both A and R are true, and R is the correct explanation of A.
Explanation: Ethanol is used in sanitisers because it evaporates quickly and damages microorganisms effectively, making it useful for hospital hygiene.

A4. Water can remove visible dirt, but cannot destroy microorganisms effectively like ethanol. Ethanol shows antimicrobial action due to its chemical properties.
Explanation: Ethanol damages the protective layer of microorganisms and evaporates quickly after use.

A5.The 70% ethanol sanitiser reduced germs rapidly because ethanol can spread easily, penetrate microbial coverings, and evaporate quickly after action.
Explanation: Ethanol acts as an effective disinfectant due to its chemical properties and fast evaporation.

A6. (c) Ethanol is effective in reducing microorganisms quickly
Explanation: The data clearly shows that ethanol-based sanitiser reduced far more germs than water within the same time period.

A7.The reaction is called esterification. One product formed is an ester called ethyl ethanoate.
Explanation: Ethanol reacts with ethanoic acid in the presence of concentrated sulphuric acid to form an ester and water.

 Boost Your Board Preparation 
To master this chapter and ace your competency-based exams, test your skills with a timed unsolved practice paper for Class 10 Chemistry. If you get stuck or want to review the ideal answering step-by-step logic, you can access the solved practice paper for Class 10 Chemistry. For quick daily revisions on carbon compounds, download this targeted Class 10 Chemistry worksheet to reinforce your core concepts.

HOTS EXTENSION QUESTIONS

Q1. Hospitals sometimes use sanitisers containing both ethanol and water instead of pure ethanol. Predict why a small amount of water may improve the effectiveness of the sanitiser.

Q2. If ethanol evaporated very slowly, how would it affect its usefulness as a hospital sanitiser? Explain using reasoning related to hygiene and practicality.

 Got Questions or Need Extra Help? 
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